U.S. President Donald Trump’s top security adviser has told a television interview that the "malign, destructive" influence of Iran and its "proxies" must be removed from Iraq, Syria, and elsewhere in the Middle East.

"It’s very difficult to see how can there be an enduring peace if one side that has perpetuated and accelerated the violence is not removed," national security adviser H.R. McMaster told U.S.-funded Alhurra television in an interview broadcast on October 25.

"So it's important for everyone in the region...to reduce the malign, destructive influence of Iran and the [Islamic] Revolutionary Guards Corps," he added.

The comments by McMaster, who is on active duty as a lieutenant general in the U.S. Army, come at a time of raised tensions in the already-unstable Middle East.

U.S.-backed forces appear on the verge of defeating Islamic State (IS) extremists in Syria and Iraq; a six-year civil war in Syria drags on; Kurdish leaders in Iraq have conducted an indepedence referendum in defiance of the government in Baghdad; Shi'ite-led rebels are fighting the government in Yemen; and the Shi’ite Hizballah movement continues to operate in Lebanon.

McMaster said he sees the effect of Tehran's influence in all the conflicts.

Iraq's Shi’ite-led government has close ties to the leadership of neighboring Iran, and experts have argued that Tehran is using militias, such as the Shi'ite-dominated Popular Mobilization Forces (PMF) and the Quds Force -- which has links to the [Islamic] Revolutionary Guards Corps (IRGC) -- to widen its influence.

On October 22, during a visit to the region, U.S. Secretary of State Rex Tillerson told Iraqi Prime Minister Haidar al-Abadi that it was it was time for Iranian-backed militias and their Iranian advisers who helped Iraq defeat IS to “go home.”

"Certainly, Iranian militias that are in Iraq, now that the fighting against [Islamic State] is coming to a close, those militias need to go home," he said.

A day later, Abadi appeared to reject Tillerson’s comments, saying the PMF "is an official institution among state bodies," which includes "Iraqi fighters who fought terrorism and defended their country."

"We should encourage them because they will be a hope for the country and the region," Abadi's office quoted him as telling Tillerson.

McMaster said the goal was not to break all connections between Baghdad and Iran, but to “contain” Tehran's “destructive” influences.

“The United States thinks that Iraq should have a relationship with Iran -- Iran is its neighbor,” he said. “But what we want is an Iraq that is strong.”

McMaster said the Iranians have done a “very good job...of infiltrating and subverting Iraqi state institutions and functions, as well as creating these militias that lay outside the Iraqi government’s control.”

“They grow these militias...and threaten governments [in the region] with those militias if those governments take action against Iranian interests,” he added.

“[Iranian leaders] want governments to be weak. They want governments to be dependent on Iran for support,” he said.

McMaster said it was important to confront Iran and its proxies elsewhere in the region, such as in Yemen, where Tehran has supported Shi’ite Huthi rebels against the Saudi Arabia-backed government.

In Syria, McMaster said the United States is working with partners in the region and allies elsewhere to forge “an enduring political settlement” to the war that has killed more than 310,000 people, created 6.1 million refugees, and internally displaced some 5 million Syrians.

McMaster indicated he did not see a role for Presidential Bashar al-Assad in any future Syrian government.

“When you look at what is necessary to bring communities together, to end the cycle of violence, it is very difficult to imagine how Assad could be a part of that,” he said.

“I mean especially with the blood that is on his hands. And how he has had a hand in destroying his own country and creating so much human suffering, using some of the most heinous weapons on Earth to commit mass murder against his own people,” McMaster added.